In what was a shock result, Rangers crashed out of the Scottish League Cup at the hands of St. Mirren earlier this week and it also ended their 27-game unbeaten run in all competitions.
The other side of Glasgow, in Celtic, could win their fourth domestic treble in a row if they beat Hearts in the Scottish Cup final at Hampden Park on Sunday, handing Neil Lennon’s men an early silverware boost.
While they have slipped off the pace in the title race this season, Celtic have been dominant in Scottish football over the last few years and McManus believes Rangers’ defeat further highlights the scale of their achievement.
He stressed that in a one-off cup game an upset result is not always surprising and it is a further glowing testament to Celtic’s record as they are on the cusp of winning a fourth treble.
Talking about Rangers’ defeat, McManus said on PLZ Soccer: “It’s a cup game, it’s a one-off.
“And I think it proves how great an achievement Celtic’s has been to go for four trebles in a row.
“On any given day you can lose a game, a cup tie.
“You don’t turn up on the night and the other team plays really well, you can find yourself out of the cup.”
Rangers are still 13 points ahead of Celtic in the title race and could move 16 points ahead if they beat Motherwell in the Scottish Premiership this afternoon.
